Methods of conditioning shoe parts



United States Patent METHODS OF CONDITIONING SHOE PARTS Hubert O. Chaplin, Roy D. McQueen, and Kenneth Lee,

Leicester, England, assignors to United Shoe Machinery Corporation, Flemington, N.J., a corporation of New Jersey No Drawing. Filed June 15, 1965, Ser. No. 464,212 US. Cl. 12-146 5 Claims Int. Cl. A43b /00; D06c 1/00 ABSTRACT OF THE DISCLOSURE This invention relates to a method of mulling shoe parts comprising subjecting a shoe part to an atmosphere at a pressure less than atmospheric pressure to withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to a moist atmosphere at a pressure above atmospheric pressure whereby moisture is forced into the evacuated interstices.

This invention relates to a method of conditioning shoe parts and, more specifically, to a process of mulling or tempering an article of leather to distribute moisture therethrough.

The shoemaking industry has been involved throughout its history in a constant and penetrating search for technical improvements. In recent years, this search has been most specifically directed toward the provision of methods and apparatus which facilitate automation. One of the steps in the normal shoemaking cycle which has impeded the advancement toward a completely automated shoemaking process is the mulling or tempering of leather. The purpose of the mulling or tempering operation is to render the leather more workable thereby to permit flexing and stretching thereof whereby shoemaking operations, particularly lasting, may be performed on the leather. Thus, mulling or tempering is a prerequisite to a number of shoemaking operations.

Heretofore, a common method for mulling or tempering leather has been to house the leather in a moist atmosphere for an extended period of time to ensure the distribution of Water throughout the leather. Another method of tempering or mulling is accomplished by dipping the leather in cold water for a period of hours and allowing it to drain. The result of these methods of mulling or tempering is uniformly moistened leather which is easily worked. These methods are, however, time consuming and, therefore, costly. Further, they do not lend them.- selves to automation and dilute the value of the automation of appurtenant operations. The need for a method of mulling or tempering leather which will facilitate the integration of this operation into an automated shoemaking cycle has been long felt and desired. However, adequate mulling or tempering cannot be sacrificed for increased automation due to the detrimental etfccts on operations dependent thereon. To do so would be to thwart the purpose of automation.

In view of the foregoing, it is an object of the present invention to provide an improved method of conditioning leather which materially decreases the time required for the mulling or tempering thereof yet attains a high degree of workability.

To this end and in accordance with a feature of the present invention, there is provided a method of conditioning shoe parts comprising confining the shoe part in a chamber and evacuating said chamber to provide a reduced pressure and thereafter admitting steam under pressure greater than atmospheric to the chamber for a period sufiicient to distribute moisture throughout the shoe part.

3,423,779 Patented Jan. 28, 1969 The above and other features of the invention will now be described, it being clearly understood that the method of this invention is equally applicable to materials used as substitutes for leather.

In order to appreciate the technological advantages and novelty of the present invention, a discussion of the changes which take place in the leather during practice of the method is necessary. The object of the present invention is to impart moisture at an elevated temperature to a shoe part, particularly an upper. The ability to accomplish this end rapidly is primarily determined by the need to replace the moisture normally present in the leather with conditioning solution having a relatively high temperature or to place the leather in a condition of abnormally high moisture content. The latter alternative is that which has been pursued in the past. However, this procedure necessarily involves longer periods of time as the effective saturation point of the leather is rapidly approached thereby increasing the difliculty in applying moisture. The present invention attempts to withdraw the moisture, air and other foreign substances normally present in the interstices between the leather fibrils by subjecting the leather article to a low pressure atmosphere, i.e., a vacuum. Thus, the moisture content of the leather is lowered and foreign substances removed thereby facilitating the permeation of hot moisture into the upper in the subsequent step of the method to be described.

The method of the subject invention comprises confining the leather upper in a chamber at a pressure less than atmospheric to withdraw air, moisture and foreign substances from the interstices of the upper. In the preferred embodiment, pressure in the chamber is not more than 5" of mercury in this step. Steam is thereafter admitted to the chamber to distribute moisture throughout the leather article. In the preferred embodiment, steam is admitted under approximately a pressure of 8 lbs. per square inch above atmospheric pressure for a period of approximately five (5) seconds. The temperature of the steam at this pressure is approximately 234 F. When the steam is admitted, a rapid increase in temperature results and, accordingly, the time interval during which the upper is exposed to the steam must be limited in order to avoid damage to the leather. In the preferred embodiment, the period of exposure to the steam is limited to from 5 to 15 seconds. In carrying out the method, it may be desirable to include in the hot moisture injected into the chamber a wetting agent which is either ionic or nonlOIllC.

The invention thus provides a method for quickly imparting a conditioning solution at an elevated temperature to an upper whereby to place the upper in a condition of maximum workability. The initial step of evacuating the chamber may be accomplished in a relatively short interval. The period of exposure of the upper to the evacuated chamber is limited to 5 to 15 seconds. Thus, a method is provided which mulls uppers rapidly and which may be conveniently integrated into an automated shoemaking process. The method may also be employed subsequent to lasting to relieve stresses as a complement to setting.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. A method of mulling shoe parts comprising subjecting the shoe part to an atmosphere at a pressure less than atmospheric pressure to withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to a moist atmosphere at a pressure above atmospheric pressure whereby moisture is forced into the evacuated interstices.

2. A method of mulling shoe parts comprising subjecting the shoe part to an atmosphere at a pressure of not more than 5" Hg to withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to a moist atmosphere at a pressure above atmospheric pressure whereby moisture is forced into the evacuated interstices.

3. A method of mulling shoe parts comprising subjecting the shoe part to an atmosphere at a pressure less than atmospheric pressure to Withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to a moist atmosphere at a pressure of approximately 8 p.s.i. whereby moisture is forced into the evacuated interstices.

4. A method of mulling shoe parts comprising subjecting the shoe part to an atmosphere at a pressure of not more than 5" Hg to withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to a moist atmosphere at a pressure of approximately 8 p.s.i. whereby moisture is forced into the evacuated interstices.

5. A method of mulling shoe parts comprising subjecting the shoe part to an atmosphere at a pressure of not more than 5" Hg to withdraw air, moisture and foreign substances from the interstices between the fibrils of the material of the shoe part and thereafter exposing the shoe part to steam at a pressure of approximately 8 p.s.i. for a period of from 5 to 15 seconds whereby moisture at an elevated temperature is forced into the evacuated interstices.

References Cited UNITED STATES PATENTS Re. 25,411 7/1963 Bromfield 12146 2,582,298 11/1952 Ushakoff 12-146 2,648,079 8/ 1953 Ushakofi 12146 2,973,531 3/1961 Bromfield 12--142 3,176,333 4/1965 Maeser 12142 PATRICK D. LAWSON, Primary Examiner. H. HAMPTON HUNTER, Assistant Examiner.

US. Cl. X.R. 

